WikiBiomeThe human microbiome encyclopediaRanked matches across titles, topics, categories, and article introductions, filtered to microbe.
A Gram-negative, obligate anaerobic genus within the family veillonellaceae (class Negativicutes, phylum Firmicutes) defined by its specialized amino acid fermentation -- the genus name literally means "acid from amino acids." Acidaminococcus ferments glutamate as its p…
A Gram-negative obligate anaerobe identified as a histamine-producing bacterium enriched in dysbiotic microbiota associated with obesity, metabolic syndrome, and metabolic endotoxemia. Allisonella is a minor but functionally significant genus whose primary clinical rele…
Alloprevotella is a genus of Gram-negative, obligate anaerobic bacteria within the family Prevotellaceae that represents a distinct clade from prevotella with specific protective roles in type 2 diabetes prevention and metabolic health. Alloprevotella depletion is one o…
A class of Gram-negative bacteria within the phylum Proteobacteria that has emerged as a causal risk factor for schizophrenia and bipolar disorder through Mendelian randomization studies. Betaproteobacteria includes genera with notable metal tolerance -- particularly wi…
A class of Gram-positive, obligate anaerobic bacteria within the phylum Firmicutes that represents the most functionally diverse and clinically significant taxonomic class in the human gut microbiome. Clostridia encompasses the dominant butyrate producers sustaining col…
An order of Gram-positive, obligate anaerobic bacteria within the class clostridia (phylum Firmicutes) that represents the single most functionally important taxonomic group in the human gut. Clostridiales encompasses the major butyrate-producing families (lachnospirace…
This page redirects to clostridioides difficile. Clostridium difficile was reclassified as Clostridioides difficile in 2016 based on phenotypic and phylogenomic analyses that demonstrated it belonged to a distinct clade within the former Clostridium genus. The reclassif…
Clostridium symbiosum is a Gram-positive, obligately anaerobic bacterium within the Clostridium cluster XIVa — a taxonomic group enriched for short-chain fatty acid (SCFA) producers and specialized bile acid metabolizers. Despite its ambiguous name (suggesting symbiotic…
Debaryomyces is a genus of ascomycetous fungi, with D. hansenii being the most clinically relevant species, that represents a prominent opportunistic pathobiont enriched in inflammatory bowel disease, particularly crohns disease. Unlike many commensal fungi, Debaryomyce…
An order of Gram-negative, strictly anaerobic sulfate-reducing bacteria (SRB) within the class Deltaproteobacteria. The defining metabolic feature of Desulfovibrionales is dissimilatory sulfate reduction -- using sulfate as a terminal electron acceptor and producing hyd…
Dialister is a genus of Gram-negative, obligate anaerobic bacteria within the family Veillonellaceae that represents one of the strongest protective associations in gut-brain-axis research. Dialister depletion is a consistent and independent biomarker of depression, anx…
A Gram-positive obligate anaerobe in the family Ruminococcaceae (Clostridium cluster IV) whose defining metabolic activity is the degradation of dietary flavonoids — the very polyphenols that serve as anti-inflammatory, antioxidant, and antimicrobial agents. When Flavon…
An order of Gram-negative, obligate anaerobic bacteria within the phylum Fusobacteriota (formerly Fusobacteria). This order-level page covers the broader taxonomic group that includes the well-characterized genus fusobacterium and its key species fusobacterium nucleatum…
A Gram-negative obligate anaerobe that occupies a paradoxical niche in the gut microbiota: as a weak butyrate producer (short-chain fatty acid), it has anti-inflammatory potential; as a virulent invasive pathobiont in inflammatory bowel disease (particularly ulcerative …
Gordonibacter urolithinfaciens is a Gram-positive, obligate anaerobic bacterium belonging to the family Eggerthellaceae that plays a specialized and critical role in polyphenol metabolism and conversion of ellagic acid to urolithin A. This microbial conversion is one of…
A Gram-negative, microaerophilic bacterium within the Epsilonproteobacteria (family Helicobacteraceae) that is the primary murine model of hepatobiliary and intestinal disease. Unlike its more famous relative helicobacter pylori, which colonizes the stomach, H. hepaticu…
A Gram-positive, obligate anaerobic genus within the Firmicutes phylum (family Oscillospiraceae or Ruminococcaceae depending on classification) that possesses a unique metabolic capability: butyrate production from lysine fermentation rather than from dietary fiber. Thi…
A Gram-negative obligate anaerobe traditionally considered an oral commensal, but increasingly recognized as an opportunistic pathobiont with the ability to translocate from oral biofilms to the gastrointestinal tract and bloodstream. Leptotrichia species are prominentl…
A Gram-positive, obligate anaerobic genus within the family lachnospiraceae (phylum Firmicutes) that was recently reclassified from Ruminococcus based on phylogenomic evidence. The key species Mediterraneibacter faecis (formerly Ruminococcus gnavus clade relatives) is a…
A class of bacteria within the phylum Tenericutes defined by the complete absence of a cell wall -- the smallest self-replicating organisms known, with minimal genomes (580 kb-1.4 Mb). While Mollicutes are best known through their pathogenic members (Mycoplasma pneumoni…
A family of Gram-positive obligate anaerobes (formerly classified as the genus Oscillospira, now reclassified into Oscillibacter and related genera within Oscillospiraceae) that serve as keystone butyrate producers in the healthy human distal colonic microbiota (Konikof…
An order of Gram-positive, obligate anaerobic bacteria within the class Clostridia (phylum Firmicutes) that has emerged as one of the most consistent markers of a healthy gut ecosystem. Oscillospirales members are butyrate producers associated with leanness and metaboli…
Parvimonas micra is a small (0.5–1.0 µm), Gram-positive, obligately anaerobic coccus originally isolated from the human oral cavity that has emerged as one of the most consistent and universally enriched pathobionts in colorectal cancer across all geographic regions, ag…
A Gram-positive, obligate anaerobic bacterium within the Firmicutes phylum (family Peptostreptococcaceae) that has emerged as a consistently enriched organism in the colorectal cancer tumor microenvironment. While fusobacterium nucleatum receives the most attention as a…
Peptostreptococcus stomatis is a Gram-positive, obligately anaerobic coccus originally isolated from the human oral cavity (oral streptococcal species) that has emerged as a carcinogenic oral pathobiont enriched in colorectal cancer, particularly in advanced stages. Unl…
A Gram-negative, obligate anaerobic genus within the phylum Bacteroidota (formerly Bacteroidetes) that was recently reclassified from Bacteroides based on phylogenomic evidence (Garcia-Lopez et al., 2019). The key species -- Phocaeicola vulgatus (formerly Bacteroides vu…
A family of Gram-negative, obligate anaerobic bacteria within the phylum Bacteroidota (formerly Bacteroidetes) that includes the genus prevotella and the recently described alloprevotella. Prevotellaceae are specialist fiber fermenters producing short-chain fatty acids,…
A filamentous fungus in the order Hypocreales (family Ophiocordycipitaceae), historically studied as an insect and nematode pathogen (P. lilacinum, formerly Paecilomyces lilacinus), now emerging as a clinically significant protective member of the gut mycobiome — and it…
Ruminococcus albus is a Gram-positive, obligate anaerobic bacterium that represents one of the primary cellulolytic (fiber-degrading) specialists in the human gut microbiota. This species constructs cellulosomes — extraordinary multi-enzyme complexes organized on bacter…
Saccharomyces cerevisiae is a unicellular budding fungus (ascomycete) ubiquitous in fermentation, brewing, bread-making, and increasingly used as a pharmaceutical probiotic (Hatoum et al. 2012). The strain S. boulardii (also called S. cerevisiae var. boulardii) is the m…
A Gram-positive, obligate anaerobic genus within the phylum Actinobacteria (family Coriobacteriaceae) that has emerged as one of the most frequently identified taxa in Mendelian randomization studies across disparate conditions -- erectile dysfunction, chronic kidney di…
A genus of Gram-positive facultative anaerobes that occupy niches ranging from benign commensals (dental plaque, skin) to acute pathogens (pharyngitis, impetigo, invasive disease). Streptococci are uniquely manganese-dependent for catalytic scavenging of reactive oxygen…
Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a Gram-positive, facultatively anaerobic coccus that exists in two clinical contexts: (1) as a major neonatal pathogen causing life-threatening meningitis and sepsis in newborns, and (2) as an enric…
A Gram-positive, facultatively anaerobic bacterium formerly classified as Streptococcus bovis biotype I that holds a unique position in clinical medicine as a sentinel organism for colorectal cancer. The detection of S. gallolyticus in blood cultures (bacteremia or endo…
Streptococcus thermophilus is a Gram-positive, facultative anaerobic coccus that is the primary probiotic species used in commercial yogurt fermentation and thermophilic dairy fermentation worldwide. Distinct from pathogenic Streptococcus species, S. thermophilus produc…
A genus of ascomycete yeasts (formerly classified as Zygosaccharomyces) found in fermentation environments (bread, wine, kombucha) and increasingly detected as a component of the human gut mycobiome. While typically at low abundance in healthy individuals, Torulaspora d…
A Gram-positive, facultatively anaerobic genus within the class Erysipelotrichia (phylum Firmicutes) that has become one of the most frequently identified taxa in gut-brain and gut-immune Mendelian randomization studies. Turicibacter sanguinis, the type species, possess…
A family of Gram-negative, obligate anaerobic bacteria within the Firmicutes phylum (class Negativicutes) that occupies a unique metabolic niche as specialized lactate utilizers. Veillonellaceae cannot ferment sugars directly -- instead, they cross-feed on lactate produ…